The present invention relates to dissolvable intraluminal stents for mammalian anastomoses.
Surgical anastomosis is the procedure of choice to relieve or correct blocked or otherwise inoperative luminal vessels. The most common vessel to which this procedure is applied is the intestine, but the procedure may also be used to correct abnormalities in blood vessels, biliary and urinary ducts, for example, as well as other vessels. However, it has been long recognized that there is a need for an essentially sutureless procedure. As early as 1892, J. B. Murphy reported sutureless anastomosis procedures using what he called an anastomosis button. J. B. Murphy "Cholecysto-Intestinal, Gastro-Intestinal Entero-Intestinal Anastomosis, An Approximation Without Sutures," Medical Record, 42(24):665-76 (Dec. 10, 1892). The techniques described by Murphy were adopted by the medical community for decades and the button became commonly called the "Murphy button." The Murphy button generally comprised a two-part metal snap which, when snapped or screwed together, would hold the two vessel stumps in close proximity until scar tissue joined the two stumps. However, one major disadvantage was that the button, when used in intestinal anastomosis procedures, would either pass several days after the surgical procedure, causing great discomfort, or would become lodged in the intestinal lumen, causing serious blockage. In addition, necrosis at the anastomosis site was prevalent when using the Murphy button.
More recently, sophisticated variants of the Murphy button have been developed and are commonly called the bowel anastomosis ring (BAR). Much of the early work of the BAR was performed and reported by T. G. Hardy et al., "A Biofragmentable Ring for Sutureless Bowel Anastomosis", Dis. Col. & Rect., 28:484-90 (1985), with later work by Hardy and others. T. G. Hardy et al., "Initial Clinical Experience With a Biofragmentable Ring for Sutureless Bowel Anastomosis," Dis. Col. & Rect., 30:55-61 (1987); J. W. Maney et al., "Biofragmentable Bowel Anastomosis Ring: Comparative Efficacy Studies in Dogs," Surgery, 103(1):56-62 (1988); C. J. Cahill et al. "Sutureless Large Bowel Anastomosis: European Experience With the Biofragmentable Anastomosis Ring," Br. J. Surg., 76(4):344-47 (1989). The BAR functions similarly to the Murphy button by holding two vessel stumps in contact with one another after securing each of the vessel stumps to the BAR with a purse-string suture and snapping the two BAR pieces together.
The BAR is fashioned from a composition that fragments under normal intraluminal conditions and these BAR fragments are expelled several days to one or two weeks after implantation. However, these fragments are irregular and sharp and are generally several millimeters to over 2 centimeters in length, thereby causing discomfort when passed. In addition, the BAR anastomosis procedure requires that purse-string sutures be in and remain in the vessel stumps to attach the vessel stumps to the BAR after the surgical procedure has been completed. These sutures may remain in the vessel tissue for several days to several weeks and their presence increases the risk of infection or leakage and edema. Moreover, despite efforts to decrease necrosis at the anastomosis, primarily accomplished by providing the BAR with interdigitating parts which lock at various gap sizes, necrosis still occurs at the site of purse-string sutures following the BAR procedure.
The present invention overcomes the inefficiencies and deficiencies of the prior art by virtue of an improved anastomosis stent for anastomosis procedures which simplifies the surgical procedure and lessens the surgical complications and postoperative discomfort to the patient.